1. Field of Invention:
This invention relates to video signal recording and reproducing apparatus capable of permitting recordings out of doors and capable of variable speed reproduction.
2. Description of the Prior Art:
The present invention may be embodied in the following example of a conventional magnetic recording and reproducing apparatus using magnetic tape as the recording medium (hereinafter referred to as "VTR").
The conventional VTR operates in such a manner that a magnetic tape is brought into contact against a cylindrical tape guide including a magnetic head over a predetermined angular distance, and, while video signals are being recorded on said tape for every one field or two fields in one of the successively formed inclined tracks, the tape is transported at a constant speed when the aforesaid video signals are being recorded or reproduced.
When reproducing the thus-recorded video signals on the magnetic tape, the tape may be transported at a different speed from that at which the recording was made, thereby slow motion, high speed reproduction and other speed-changed reproductions are made possible. The aforesaid high speed reproduction is advantageous for skipping an identified portion of the recorded tape, or searching.
When in normal recording or reproducing operation, it is customary in the conventional VTR or tape recorder that a pinch roller and a capstan contact across the magnetic tape, and the aforesaid capstan is driven to rotate by an electric motor or other suitable drive source, thus running the tape.
Also for high speed reproduction in addition to the normal speed, there are known two methods of transporting the tape at high speed. One method is that after the tape is taken out of contact with the pinch roller and capstan, the reel-driving rotors are caused to rotate at a high speed, or the so-called "fast" feed or "fast" rewind mode is set on the VTR to carry out high speed reproduction. The other method is that the capstan is caused to rotate at a higher speed than when in the normal recording or reproducing mode.
The former method, owing to the fact that the running speeds of the tape when in the fast feed and fast rewind modes are generally considerably higher than when in the recording mode, is relatively easy to realize for high speed reproduction. However, it has a disadvantage in that as the diameter of the wound tape changes, the running speed of the tape changes correspondingly.
The latter method, because the tape speed depends upon the number of revolutions of the capstan motor, does provide for a small change in the running speed. However, since the number of revolutions of the capstan motor depends upon the drive voltage, and because, in the case of a portable type VTR utilizing a battery, the availability of the electrical power source is limited, it has been found that in actual practice high speed reproduction cannot be carried out at greatly increased speeds.